Large dome-shaped structures have been constructed by first constructing an extensive temporary internal scaffolding. The arch members and ribs are supported by internal scaffolding during construction. When the dome has been completed, the scaffolding is dismantled and removed from inside the dome structure.
Where the diameter and height of the dome constructed by these standard methods exceeds the height and reach of standard mobile cranes, it is expensive to lift the materials to the final elevation of the structure, and the workmen are required to work at extreme heights and on curved or inclined surfaces which greatly increases the danger. The cost of erecting and dismantling the huge scaffolding which not only must support the workmen but also support the dome structure during construction is exceedingly costly and has greatly inhibited the construction of these structures.
Since many of the structural members are curved and most of the joints are angularly related, it is difficult to erect such structures at the site where dimensionally accurate jigs and factory controlled conditions are impossible.
A dome having similar dimensions as the structure described in this specification was designed by the La Farge Company of Montreal, Canada. The structure was to be erected using internal scaffolding and because standard cranes could not lift the arch members as a single unit, they were to be constructed by bolting a series of straight members together at great cost due to the need for many flange connections and a great deal of labor in the assembly.
A different type dome structure is shown in Fink, U.S. Pat. No. 3,417,520 granted Dec. 24, 1968. Fink raised the individual arch members with cranes and then carried out the rest of the construction with conventional methods using either scaffolding or mobile work platforms. The arch members were not jointed nor were entire panels prefabricated on the ground.